<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
#div1 {width:200px; height:100px; background:#CCC; border:1px solid #999; display:none;}
</style>
</head>

<body>
<input type="checkbox" onmouseover="document.getElementById('div1').style.display='block';" onmouseout="document.getElementById('div1').style.display='none';" />
<div id="div1">
	为了您的信息安全。。。。
</div>
</body>
</html>
